Ryan ASCII notation

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A system of using ASCII characters to notate any fractional frequency in Just Intonation. Created by the musician and theorist David Ryan

* Preprint: http://arxiv.org/pdf/1508.07739

**Abstract:**
Musical notation systems provide ways of recording which notes musicians should play at which times. One essential parameter described is the frequency. For twelve-note tuning systems the frequency can be described using letters A to G with sharp or flat symbols. For Just Intonation tuning systems these symbols are insufficient. This paper provides a system for describing any frequency which is a rational number multiplied by a suitable base frequency. Explicit notation is given for low prime numbers, and an algorithm for higher primes described.

**Key features:**
Can be inputted by computer keyboard alone (ASCII characters)
Can freely transpose keys in JI - done by multiplying notations - any two notations can be easily multiplied
Simple notations exist for 3-limit, 5-limit, 7-limit JI notes
Look-up table for providing ASCII notation for higher primes (11/8, 109/100, etc)
Algorithm for deriving these notations
Very compact notation for octave equivalence classes
Good for describing all the notes on a 5-limit or 7-limit tone lattice

**Challenges:**
Octaves are not sequential - easier to understand octave equivalence classes than exact notes . ( Example: C = 1/1 F = 4/3 G = 3/4 but 3/2 = `G so 3/2 requires an octave modifier to describe.)

**Notation examples:**

//2-limit://
C = 1/1
`C = 2/1 (definition of octave modifier using ` character to prefix)
,C = 1/2 (definition of octave modifier using , character to prefix)
,,,C = 1/8

//3-limit://
F = 4/3 (definitions of the 7 note names here)
C = 1/1
G = 3/4
D = 9/16
A = 27/64
E = 81/256
B = 243/1024
Bb = 16/9 (definition of a flat b character)
F# = 729/4096 (definition of a sharp # character)
C# = 2187/16384 (this is equivalent to a sharp # character)
Cb = 16384/2187 (this is equivalent to a flat b character)
`G = 3/2
```D = 9/2

//5-limit://
E' = 5/4 (definition of ' modifier)
Ab. = 4/5 (definition of . modifier)
A' = 4/3
``E' = 5/1
`B' = 15/8

//7-limit//
Bb~7 = 7/8 (definition of ~7 modifier)
D_7 = 8/7 (definition of _7 modifier)
F~7 = 21/16
`Bb~7 = 7/4
`F~7 = 21/16
Eb~7 = 7/6

//Higher p-limits//
F#~11 = 11/8 (definition of ~11 modifier)
Gb_11 = 8/11 (definition of _11 modifier)
``F#~11 = 11/2
B~11 = 11/6
Ab~13 = 13/16
C#~17 = 17/16
Eb~19 = 19/16
F#~23 = 23/32
etc (separate definition for each prime)

**Calculation examples**
The golden rule in this notation is: to derive notation for a more complicated fraction, break it down into simpler fractions; fractions with notation already known. In particular, separate out the fractions for each higher prime.

55/32 = (11/8)*(5/4) = F#~11 * E' = A#'~11
7/5 = (7/8)*(4/5)*(2/1) = Bb~7 * Ab. * `C = `Bb.~7 * Ab = `Gb.~7
30/1 = (2/1)*(3/1)*(5/1) = (32/1)*(3/4)*(5/4) = `````C * G * E' = `````G' * E = `````B' (Notice how modifiers ` for octave and ' for prime 5 can be moved about freely)
19/13 = (19/16) * (16/13) = Eb~19 * (Ab~13)^-1 = Eb~19 * E_13 = G~19_13

**Other links**
Some music created using this notation is available at:
* Dave Ryan's SoundCloud page: https://soundcloud.com/daveryan23

Original HTML content:

<html><head><title>Ryan ASCII notation</title></head><body>A system of using ASCII characters to notate any fractional frequency in Just Intonation. Created by the musician and theorist David Ryan<br />
<br />
<ul><li>Preprint: <!-- ws:start:WikiTextUrlRule:88:http://arxiv.org/pdf/1508.07739 --><a class="wiki_link_ext" href="http://arxiv.org/pdf/1508.07739" rel="nofollow">http://arxiv.org/pdf/1508.07739</a><!-- ws:end:WikiTextUrlRule:88 --></li></ul><br />
<strong>Abstract:</strong><br />
Musical notation systems provide ways of recording which notes musicians should play at which times. One essential parameter described is the frequency. For twelve-note tuning systems the frequency can be described using letters A to G with sharp or flat symbols. For Just Intonation tuning systems these symbols are insufficient. This paper provides a system for describing any frequency which is a rational number multiplied by a suitable base frequency. Explicit notation is given for low prime numbers, and an algorithm for higher primes described.<br />
<br />
<strong>Key features:</strong><br />
Can be inputted by computer keyboard alone (ASCII characters)<br />
Can freely transpose keys in JI - done by multiplying notations - any two notations can be easily multiplied<br />
Simple notations exist for 3-limit, 5-limit, 7-limit JI notes<br />
Look-up table for providing ASCII notation for higher primes (11/8, 109/100, etc)<br />
Algorithm for deriving these notations<br />
Very compact notation for octave equivalence classes<br />
Good for describing all the notes on a 5-limit or 7-limit tone lattice<br />
<br />
<strong>Challenges:</strong><br />
Octaves are not sequential - easier to understand octave equivalence classes than exact notes . ( Example: C = 1/1 F = 4/3 G = 3/4 but 3/2 = `G so 3/2 requires an octave modifier to describe.)<br />
<br />
<strong>Notation examples:</strong><br />
<br />
<em>2-limit:</em><br />
C = 1/1<br />
`C = 2/1 (definition of octave modifier using ` character to prefix)<br />
,C = 1/2 (definition of octave modifier using , character to prefix)<br />
,,,C = 1/8<br />
<br />
<em>3-limit:</em><br />
F = 4/3 (definitions of the 7 note names here)<br />
C = 1/1<br />
G = 3/4<br />
D = 9/16<br />
A = 27/64<br />
E = 81/256<br />
B = 243/1024<br />
Bb = 16/9 (definition of a flat b character)<br />
F# = 729/4096 (definition of a sharp # character)<br />
C# = 2187/16384 (this is equivalent to a sharp # character)<br />
Cb = 16384/2187 (this is equivalent to a flat b character)<br />
`G = 3/2<br />
```D = 9/2<br />
<br />
<em>5-limit:</em><br />
E' = 5/4 (definition of ' modifier)<br />
Ab. = 4/5 (definition of . modifier)<br />
A' = 4/3<br />
``E' = 5/1<br />
`B' = 15/8<br />
<br />
<em>7-limit</em><br />
Bb~7 = 7/8 (definition of ~7 modifier)<br />
D_7 = 8/7 (definition of _7 modifier)<br />
F~7 = 21/16<br />
`Bb~7 = 7/4<br />
`F~7 = 21/16<br />
Eb~7 = 7/6<br />
<br />
<em>Higher p-limits</em><br />
F#~11 = 11/8 (definition of ~11 modifier)<br />
Gb_11 = 8/11 (definition of _11 modifier)<br />
``F#~11 = 11/2<br />
B~11 = 11/6<br />
Ab~13 = 13/16<br />
C#~17 = 17/16<br />
Eb~19 = 19/16<br />
F#~23 = 23/32<br />
etc (separate definition for each prime)<br />
<br />
<strong>Calculation examples</strong><br />
The golden rule in this notation is: to derive notation for a more complicated fraction, break it down into simpler fractions; fractions with notation already known. In particular, separate out the fractions for each higher prime.<br />
<br />
55/32 = (11/8)*(5/4) = F#~11 * E' = A#'~11<br />
7/5 = (7/8)*(4/5)*(2/1) = Bb~7 * Ab. * `C = `Bb.~7 * Ab = `Gb.~7<br />
30/1 = (2/1)*(3/1)*(5/1) = (32/1)*(3/4)*(5/4) = <!-- ws:start:WikiTextRawRule:00:```` --><!-- ws:end:WikiTextRawRule:00 -->`C * G * E' = <!-- ws:start:WikiTextRawRule:01:```` --><!-- ws:end:WikiTextRawRule:01 -->`G' * E = <!-- ws:start:WikiTextRawRule:02:```` --><!-- ws:end:WikiTextRawRule:02 -->`B' (Notice how modifiers ` for octave and ' for prime 5 can be moved about freely)<br />
19/13 = (19/16) * (16/13) = Eb~19 * (Ab~13)^-1 = Eb~19 * E_13 = G~19_13<br />
<br />
<strong>Other links</strong><br />
Some music created using this notation is available at:<br />
<ul><li>Dave Ryan's SoundCloud page: <!-- ws:start:WikiTextUrlRule:89:https://soundcloud.com/daveryan23 --><a class="wiki_link_ext" href="https://soundcloud.com/daveryan23" rel="nofollow">https://soundcloud.com/daveryan23</a><!-- ws:end:WikiTextUrlRule:89 --></li></ul></body></html>